A Scalable Approach to Na2FeP2O7@Carbon/Expanded Graphite as a Low‐Cost and High‐Performance Cathode for Sodium‐Ion Batteries. Issue 18 (30th September 2020)

• Record Type: Journal Article
• Authors: Zeng, Liyan; Li, Fangkun; Xu, Xijun; Liu, Zhengbo; Shen, Jiadong; Zhang, Dechao; Li, Yu; Liu, Jun
• Is Part Of: ChemElectroChem. Volume 7:Issue 18(2020)
• Page Start: 3874
• Page End: 3882
• Publication Date: 2020-09-30
• Subjects: Na2FeP2O7 -- carbon encapsulation -- expanded graphite -- cathode materials -- sodium-ion batteries; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202001087
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: Sodium‐ion batteries (SIBs) are the most promising candidates as alternatives to lithium‐ion batteries (LIBs), owing to the natural abundance of sodium salt and the low cost. However, the commercial application of SIBs is principally hampered by the absence of suitable cathode materials. Herein, a novel Na2 FeP2 O7 @carbon/expanded graphite (NFPO@C/EG) composite with a unique microstructure was developed through a scalable sol‐gel process followed by a ball‐milling procedure with expanded graphite. Benefiting from the multiscale carbon‐modified structure, the NFPO@C/EG effectively improves the electronic conductivity and, at the same time, shortens the path of sodium ion transmission. As a consequence, the NFPO@C/EG cathode presents a much higher specific capacity and more stable cycling stability than NFPO@C and NFPO. The unique design of NFPO@C/EG endows a high ratio of pseudocapacitance contribution and a large Na + diffusion coefficient. As a consequence, the NFPO@C/EG cathode displays stable cycle performance (82 mAh g −1 over 400 cycles at 232 mA g −1 ) and superior rate capability (60 mAh g −1 at a high charge/discharge density of 2320 mA g −1 ). This multiscale carbon‐modified design concept builds an avenue for the practical application of polyanionic cathode materials and promotes the development of low‐cost SIBs. Abstract : High carb : Multiscale carbon‐modified Na2 FeP2 O7 @carbon/extended graphite is successfully fabricated through a scalable sol‐gel method combined with a ball‐milling procedure. Owing to the double carbon‐modified nanostructure, this cathode ensures fast Na + diffusion kinetics, resulting in superior cycle performance for sodium‐ion batteries.